Method and device for treating electro-deposition nickel anolyte

Abstract

The present application relates to the field of electro-deposition nickel anolyte treatments. Disclosed are a method and a device for treating an electro-deposition nickel anolyte. The method comprises: mixing a calcium-containing neutralizer I with an electro-deposition nickel anolyte A to perform a deacidification treatment, and thereby obtaining a deacidified slurry; subjecting the deacidified slurry to a first solid-liquid separation treatment, so as to obtain a nickel-containing solution and a calcium sulfate slag; mixing a calcium-containing neutralizer II with the nickel-containing solution to perform a desilication and de-leading treatment, thereby obtaining a desilicated and de-leaded slurry; subjecting the desilicated and de-leaded slurry to a second solid-liquid separation treatment to obtain desilicated and de-leaded slag and a nickel-containing pre-impurity-removal solution having a silicon content of less than or equal to 50 mg / L; and subjecting the nickel-containing pre-impurity-removal solution to an impurity removal treatment, so as to obtain a nickel-enriched impurity-removed solution having a calcium content of less than or equal to 50 mg / L. The method provided in the present application can not only reduce the production costs, but also generates no wastewater. Moreover, the method can remove both the calcium introduced by a calcium salt and impurity ions that are circulated and enriched in the anolyte, and the generated waste residue serves as a building material or a neutralizing agent, and is environmentally friendly.

Description

Method and apparatus for treating electrowinning nickel anolyte

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202510067813.0, filed on January 15, 2025, entitled “Method and Apparatus for Processing Electrolytic Nickel Anode Liquid”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of electrolytic nickel anolyte treatment, and more specifically to a method and apparatus for treating electrolytic nickel anolyte. Background Technology

[0004] Electrowinning can employ an insoluble anode and a pure nickel starting plate as the cathode, allowing the metal to be extracted from the electrolyte to deposit and precipitate on the cathode, thus achieving the purpose of metal extraction. During electrowinning, water electrolysis occurs at the anode, and the anolyte continuously accumulates acid.

[0005] The anolyte contains a large amount of acid and nickel, which can be recycled and used to prepare the catholyte. In related technologies, the nickel in the anolyte is usually precipitated with alkali first, and then the precipitate is dissolved with acid before being used to prepare the catholyte. However, these technologies cannot balance technical economy and catholyte quality. Summary of the Invention

[0006] The purpose of this application is to provide a method and apparatus for treating electrolytic nickel anolyte to improve the economic efficiency and quality of anolyte treatment.

[0007] To achieve the above objectives, a first aspect of this application provides a method for processing electrolytic nickel anolyte, the method comprising:

[0008] Deacidification process: Calcium-containing neutralizing agent I is mixed with electrolytic nickel anolyte A to carry out deacidification treatment, and a deacidified slurry is obtained;

[0009] First solid-liquid separation process: The deacidified slurry is subjected to a first solid-liquid separation treatment to obtain a nickel-containing solution and calcium sulfate slag;

[0010] Desiliconization and lead removal process: Calcium neutralizing agent II is mixed with the nickel-containing solution to perform desiliconization and lead removal treatment, resulting in a desiliconized and lead-removed slurry;

[0011] The second solid-liquid separation process involves subjecting the desiliconized and lead-removed slurry to a second solid-liquid separation treatment to obtain desiliconized and lead-removed slag and a nickel-containing pre-removal liquid with a silicon content ≤50mg / L.

[0012] Impurity removal process: The nickel-containing pre-removal solution is subjected to impurity removal treatment to obtain a nickel-rich post-removal solution with a calcium content ≤50mg / L.

[0013] Optionally, the method satisfies at least one of the following conditions:

[0014] A. The method further includes a dissolution step: mixing the electrolytic nickel anolyte B with a nickel-containing raw material to carry out a leaching reaction, thereby obtaining a nickel-containing leachate;

[0015] B. The method further includes a pH adjustment step: the nickel-rich impurity-removed solution is mixed with a pH buffer and a nickel sulfate solution for pH adjustment treatment to obtain a pH-adjusted solution with a pH value of 3-4.

[0016] Optionally, the method satisfies at least one of the following conditions:

[0017] A. Calcium-containing neutralizing agent I is mixed with electrolytic nickel anolyte A in powder form for deacidification treatment;

[0018] B. The endpoint pH value of the deacidification treatment is 2.5-3.0;

[0019] C. The reaction time for the deacidification treatment is 3-6 hours;

[0020] D. The calcium-containing neutralizing agent I and the calcium-containing neutralizing agent II each independently comprise at least one of CaCO3, CaO and Ca(OH)2;

[0021] E. Calcium-containing neutralizing agent I includes limestone powder and desiliconized and lead-removing slag;

[0022] F. The particle size D of the calcium-containing neutralizing agent I and the calcium-containing neutralizing agent II 95 All are less than 150 μm;

[0023] G. The calcium-containing neutralizing agent II is pulped before use, and the pulping includes: mixing the calcium-containing neutralizing agent II with water to obtain a neutralizing agent slurry; the concentration of the calcium-containing neutralizing agent II in the neutralizing agent slurry is 10-30 wt%;

[0024] H. The deacidification process includes at least three deacidification treatments, with at least 50% of the total amount of calcium neutralizing agent I added in the first deacidification treatment;

[0025] I. The composition of electrolytic nickel anolyte A or electrolytic nickel anolyte B includes: Ni 40-70 g / L, Ca 4-10 mg / L, Mg 1000-1700 mg / L, Si 50-150 mg / L, Co 1-7 mg / L, Cu 0.5-1.5 mg / L, Zn 0.05-0.2 mg / L, Fe 0.5-1 mg / L, Pb 0.3-2 mg / L, and sulfuric acid 40-60 g / L;

[0026] J. The nickel sulfate solution includes a nickel sulfate solution obtained by removing impurities from the nickel-containing leaching solution produced in the dissolution process.

[0027] Optionally, the first solid-liquid separation process includes:

[0028] The deacidified slurry is filtered to obtain filtrate and filter residue. The filter residue is then subjected to a first wash and a second wash in sequence. The wash water from the first wash is incorporated into the filtrate to form the nickel-containing solution. The filter residue after the first wash is then subjected to a second wash to obtain calcium sulfate residue. The wash water from the second wash is recycled for the first wash. The nickel content of the calcium sulfate residue is ≤0.05wt%.

[0029] Optionally, the desiliconization and lead removal process includes a multi-stage desiliconization and lead removal process performed sequentially.

[0030] Optionally, the method satisfies one or both of the following conditions:

[0031] A. The final pH value of the first stage of the multi-stage desiliconization and lead removal process is 3.5-4, and the final pH value of the multi-stage desiliconization and lead removal process is 5-6.

[0032] B. The desiliconization and lead removal process includes a first-stage desiliconization and lead removal process, a second-stage desiliconization and lead removal process, and a third-stage desiliconization and lead removal process performed sequentially. The final pH value of the first-stage desiliconization and lead removal process is 3.5-4, the final pH value of the second-stage desiliconization and lead removal process is 4-5, and the final pH value of the third-stage desiliconization and lead removal process is 5-6.

[0033] C. The reaction time for the desiliconization and lead removal treatment is 2-4 hours.

[0034] Optionally, the second solid-liquid separation step includes:

[0035] Filtration treatment: The slurry after desiliconization and lead removal is subjected to pressure filtration to obtain desiliconized and lead-removed slag and filtrate.

[0036] Precision filtration: The filtrate from the pressure filter is precision filtered to obtain the nickel-containing pre-purification liquid.

[0037] Optionally, the calcium content of the nickel-containing pre-purification solution is 450-650 mg / L.

[0038] Optionally, the impurity removal process includes:

[0039] Extraction and impurity removal: The nickel-containing pre-extraction solution is subjected to extraction and impurity removal treatment to obtain a nickel-containing raffinate;

[0040] Oil removal: The nickel-containing raffinate is subjected to oil removal treatment to obtain a nickel-rich purified liquid.

[0041] Optionally, the nickel-containing raffinate has the following properties: pH value of 2.5-3.5 and magnesium content ≤2g / L; the nickel-rich purified liquid has the following properties: oil content ≤2mg / L.

[0042] Optionally, the extraction and impurity removal includes:

[0043] The nickel-containing raffinate before impurity removal is mixed with the saponified extractant for extraction and impurity removal treatment to obtain a nickel-containing raffinate; wherein the saponification rate of the extractant is 10-40%.

[0044] Optionally, the mixture may also include mixing a portion of the nickel-containing raffinate with the filter press filtrate, wherein the weight of the nickel-containing raffinate is 3-7% of the weight of the filter press filtrate.

[0045] Optionally, the weight ratio of the electrolytic nickel anolyte A to the electrolytic nickel anolyte B is 1:0.6-1.5.

[0046] The second aspect of this application provides an apparatus for processing electrolytic nickel anolyte, the apparatus comprising: a deacidification unit including a plurality of deacidification tanks connected in series, the plurality of deacidification tanks being used to mix a calcium-containing neutralizing agent I with electrolytic nickel anolyte A to perform continuous multi-stage deacidification treatment to obtain a deacidified slurry;

[0047] The first filtration unit is used to perform solid-liquid separation treatment on the deacidified slurry obtained from the deacidification unit to obtain a nickel-containing solution and calcium sulfate slag.

[0048] The desiliconization and lead removal unit includes multiple desiliconization and lead removal tanks connected in series. These multiple desiliconization and lead removal tanks are used to mix calcium-containing neutralizing agent II with the nickel-containing solution to perform continuous multi-stage desiliconization and lead removal treatment to obtain a desiliconized and lead-removed slurry.

[0049] The second filtration unit is used to perform solid-liquid separation treatment on the desiliconized and lead-removed slurry obtained from the desiliconized and lead-removed unit to obtain desiliconized and lead-removed slag and nickel-containing impurity-removed pre-liquid.

[0050] The first impurity removal unit is used to remove impurities from the nickel-containing pre-removal liquid obtained by the second filtration unit to obtain a nickel-rich post-removal liquid.

[0051] Optionally, the device satisfies at least one of the following conditions:

[0052] A. The apparatus further includes: a dissolution unit, which is used to mix the electrolytic nickel anolyte B with a nickel-containing raw material to carry out a leaching reaction to obtain a nickel-containing leachate;

[0053] B. The device further includes: a pH adjustment unit, which includes a pH adjustment reaction tank, and the pH adjustment unit is connected to the first impurity removal unit.

[0054] Furthermore, the device satisfies at least one of the following conditions:

[0055] A. The first filtration unit includes a first belt filter press and a wash water storage tank. The material inlet of the first belt filter press is connected to the deacidification unit, the filtrate outlet of the first belt filter press is connected to the wash water storage tank, and the wash water storage tank is connected to the desiliconization and lead removal unit.

[0056] B. Multiple desiliconization and lead removal tanks connected in series are distributed in a stepped decreasing manner;

[0057] C. The desiliconization and lead removal unit is connected to the pulping unit, which includes a powder silo, a screw feeder, a pulping tank, and a calcium neutralizer II slurry storage tank connected in sequence; the calcium neutralizer II slurry storage tank is connected to the desiliconization and lead removal tank and is used to supply calcium neutralizer II slurry to the desiliconization and lead removal tank.

[0058] D. The second filtration unit includes a second belt filter press, a desiliconized and lead-removed liquid tank, and a precision filter connected in sequence; wherein, the filter element of the precision filter is a PE filter element with a pore size ≤0.5μm;

[0059] E. The first impurity removal unit includes a box-type extraction device and an oil removal device. The material inlet of the box-type extraction device is connected to a precision filter, and the material outlet of the box-type extraction device is connected to the oil removal equipment and the desiliconized and lead-removed liquid tank, respectively.

[0060] F. The apparatus further includes a second impurity removal unit for removing impurities from the nickel-containing leaching solution, the second impurity removal unit being connected to the pH adjustment unit.

[0061] Compared with related technologies, this application has at least the following beneficial effects:

[0062] (1) This application uses a calcium-containing neutralizing agent to replace high-value neutralizing agents such as liquid alkali and sodium carbonate, which is inexpensive and readily available, thus reducing production costs.

[0063] (2) The method of this application adopts a two-stage method: the first stage uses the lowest value calcium-containing neutralizing agent to neutralize and deacidify, and the calcium sulfate slag produced can be sold as building material after being washed and qualified; the second stage uses calcium-containing neutralizing agent to continue to adjust the pH to remove silicon and lead, and the slag produced can be sent to other nickel sulfate production lines as neutralizing agent after simple washing, which is environmentally friendly.

[0064] (3) In the method of this application, after desiliconization and lead removal, the slurry is subjected to solid-liquid separation to remove impurities, which can remove the calcium introduced by calcium salt and the impurity ions that are circulated and enriched in the anolyte.

[0065] (4) In the method of this application, deacidification and desulfurization are mainly carried out through calcium sulfate slag, which does not produce wastewater and does not require the construction of corresponding wastewater treatment equipment such as nickel recovery and MVR evaporator. Attached Figure Description

[0066] Figure 1 shows a partial flowchart of the method for treating electrolytic nickel anolyte provided in Example 1;

[0067] Figure 2 shows a partial flow diagram of the apparatus for processing electrolytic nickel anolyte provided in Example 1. Detailed Implementation

[0068] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0069] The terms “comprising,” “including,” “having,” “containing,” or any other variations thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0070] In this document, wt% refers to weight percentage, and unless otherwise specified, all percentages are by mass. Room temperature refers to a temperature of 20±5℃.

[0071] In this article, the particle size D 95 It refers to the particle size at which the cumulative particle size distribution number of particles measured by a laser particle size analyzer reaches 95%, that is, 95% of the particles are smaller than (or equal to) this particle size.

[0072] In this document, unless otherwise explicitly stated and limited, the term "connection" should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. For example, the deacidification unit and the first filtration unit can be indirectly connected through pipes or a slurry pump.

[0073] In this article, electrolytic nickel anolyte refers to the solution containing H2 produced by the reaction in the electrolytic nickel anolyte chamber. + The nickel-containing solution, nickel-concentrated anolyte A and nickel-concentrated anolyte B are both nickel-concentrated anolytes. For example, the nickel-concentrated anolyte can be formed by reacting the nickel-lean solution after electrowinning with H-containing solutions in the anode chamber. +In some specific examples, the composition of the electrowinning nickel anolyte obtained by mixing ionic solutions includes: Ni 40-70 g / L, Ca 4-10 mg / L, Mg 1000-1700 mg / L, Si 50-150 mg / L, Co 1-7 mg / L, Cu 0.5-1.5 mg / L, Zn 0.05-0.2 mg / L, Fe 0.5-1 mg / L, Pb 0.3-2 mg / L, and sulfuric acid 40-60 g / L.

[0074] In related technologies, the electrodeposition process can employ an insoluble anode and a pure nickel starting electrode as the cathode, allowing the metal to be extracted from the electrolyte to deposit and precipitate on the cathode, thereby achieving the purpose of metal extraction. During the electrodeposition process, an electrolysis reaction of water occurs at the anode, and the anolyte continuously accumulates acid.

[0075] The anolyte contains a large amount of acid and nickel, which can be recycled and used to prepare the catholyte. In related technologies, the nickel in the anolyte is usually precipitated with alkali first, and then the precipitate is dissolved with acid. The solution obtained after dissolution is used to prepare the catholyte. However, it is difficult to balance the technical economy and the quality of the catholyte in these technologies.

[0076] In view of the above problems, as mentioned above, the first aspect of this application provides a method for processing electrolytic nickel anolyte, the method comprising:

[0077] Deacidification process: Calcium-containing neutralizing agent I is mixed with electrolytic nickel anolyte A to carry out deacidification treatment, and a deacidified slurry is obtained;

[0078] First solid-liquid separation process: The deacidified slurry is subjected to a first solid-liquid separation treatment to obtain a nickel-containing solution and calcium sulfate slag;

[0079] Desiliconization and lead removal process: Calcium neutralizing agent II is mixed with the nickel-containing solution to perform desiliconization and lead removal treatment, resulting in a desiliconized and lead-removed slurry;

[0080] The second solid-liquid separation process involves subjecting the desiliconized and lead-removed slurry to a second solid-liquid separation treatment to obtain desiliconized and lead-removed slag and a nickel-containing pre-removal liquid with a silicon content ≤50mg / L.

[0081] Impurity removal process: The nickel-containing pre-removal solution is subjected to impurity removal treatment to obtain a nickel-rich post-removal solution with a calcium content ≤50mg / L.

[0082] In some embodiments, the method for treating electrolytic nickel anolyte provided in this application includes a deacidification step, a first solid-liquid separation step, a desiliconization and lead removal step, a second solid-liquid separation step, and an impurity removal step. The obtained nickel-rich, impurity-removed liquid can be used to prepare cathode liquid. In the deacidification step, a calcium-containing neutralizing agent I is used instead of liquid alkali for deacidification treatment, reducing processing costs. The calcium sulfate slag produced in the first solid-liquid separation step can be sold as building material, reducing wastewater treatment pressure and thus reducing the need for supporting wastewater treatment equipment such as nickel recovery and MVR systems, further reducing processing costs. The impurity removal step removes calcium ions and other impurity ions introduced by calcium-containing neutralizing agents I and II from the system. In the desiliconization and lead removal step, calcium-containing neutralizing agent II is used to further increase the pH, allowing silicon to co-precipitate with calcium sulfate, and suspended lead sulfate to be adsorbed and precipitated, thereby reducing the adverse effects of silicon on the power consumption of the electrolytic nickel process and the adverse effects of lead on the lead content in the electrolytic nickel product. The desiliconization and lead removal processes, as well as the impurity removal processes, can control the content of key impurity ions in the anolyte, thereby improving the quality of the cathode solution prepared after nickel-rich impurity removal.

[0083] In some embodiments, the method of treating electrolytic nickel anolyte further includes:

[0084] Dissolution process: The electrolytic nickel anolyte B is mixed with nickel-containing raw materials to carry out a leaching reaction, resulting in a nickel-containing leachate.

[0085] It is understandable that the method of treating electrolytic nickel anolyte can also include liquid separation, which divides the electrolytic nickel anolyte to be treated into two parts: electrolytic nickel anolyte A and electrolytic nickel anolyte B.

[0086] In the above embodiments, the electrolytic nickel anolyte is separated into two parts. A portion of the electrolytic nickel is mixed with nickel-containing raw materials for a leaching reaction to obtain a nickel-containing leachate. After extraction, degreasing, and other impurity removal treatments, a nickel sulfate solution is obtained. On the one hand, this can be used to replenish the nickel in the electrolytic nickel system. The acid in the electrolytic nickel anolyte B is utilized in the leaching reaction, further improving the system's economy. On the other hand, when electrolytic nickel anolyte B is mixed with nickel-containing raw materials for a leaching reaction, such as during high-pressure leaching, a small amount of water can evaporate in the pressurized section, which can also promote the system's water balance. Furthermore, by combining the treatment processes of electrolytic nickel anolyte A and electrolytic nickel anolyte B, impurities can be discharged from the system through desiliconization and lead removal processes and impurity removal processes. The acid in the electrolytic nickel anolyte B can be utilized through a dissolution process. At the same time, the water introduced during the washing of filter residue in the first solid-liquid separation process can partially evaporate during leaching, promoting the system's water balance and reducing costs.

[0087] In the above embodiments, the nickel-containing raw material can be a sulfur-containing nickel material, for example, it can be high-grade nickel matte.

[0088] In some embodiments, the nickel-containing leachate is further subjected to a purification treatment to obtain a nickel sulfate solution. In some examples, P507 (Chinese name: 2-ethylhexyl phosphate mono-2-ethylhexyl ester) is used to perform extraction purification treatment on the nickel-containing leachate.

[0089] In some embodiments, the weight ratio of the electrolytic nickel anolyte A to the electrolytic nickel anolyte B is 1:0.6-1.5. A suitable weight ratio is beneficial for controlling the impurity content of the system and for maintaining the balance of water and sulfur elements in the system.

[0090] In some embodiments, calcium-containing neutralizing agent I is mixed with electrolytic nickel anolyte A in powder form for deacidification treatment. Choosing calcium-containing neutralizing agent I, such as calcium carbonate, results in less agglomeration during mixing, eliminates the need for slurrying before use, avoids the introduction of slurrying water, and reduces costs associated with using calcium-containing neutralizing agent I powder.

[0091] In some embodiments, the endpoint pH of the deacidification treatment is 2.5-3.0, for example, it can be any value between 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, or 2.5-3.0. A suitable endpoint pH for the deacidification treatment is beneficial to further improve economic efficiency. Too low a pH will result in more residual acid, while too high a pH will produce nickel crystal particles, thereby leading to nickel loss.

[0092] The deacidification treatment time can be adjusted according to the amount of electrolytic nickel anolyte to be treated. In some embodiments, the deacidification treatment reaction time is 3-6 hours, for example, any value among 3 hours, 4 hours, 5 hours, 6 hours or 3-6 hours.

[0093] In some embodiments, calcium neutralizing agent I and calcium neutralizing agent II each independently include at least one of CaCO3, CaO and Ca(OH)2.

[0094] In some embodiments, the calcium-containing neutralizing agent I comprises limestone powder and desilication and lead removal slag. When the desilication and lead removal slag is used with the calcium-containing neutralizing agent I, the Ni impurities in the slag can be recovered in the deacidification process, while the silicon and lead impurities in the slag can be removed from the system along with the calcium sulfate slag, further reducing Ni loss and improving process economy. In some embodiments, CaCO3 is provided by limestone powder, CaO by quicklime powder, and Ca(OH)2 by hydrated lime powder. Choosing suitable raw materials not only reduces costs but also allows for use without pulping, avoiding the introduction of pulping water and further reducing costs.

[0095] In some embodiments, the particle size D of the calcium-containing neutralizing agent I and the calcium-containing neutralizing agent II is... 95 Less than 150μm.

[0096] In some embodiments, the calcium-containing neutralizing agent II is pulped before use, the pulping comprising: mixing the calcium-containing neutralizing agent II with water to obtain a neutralizing agent slurry; the concentration of the calcium-containing neutralizing agent II in the neutralizing agent slurry is 10-30 wt%.

[0097] In some embodiments, the deacidification process includes at least a first deacidification treatment and a second deacidification treatment. Further, at least 50% of the total amount of calcium neutralizing agent I is added in the first deacidification treatment.

[0098] It is understandable that the deacidification process may include one or more other deacidification processes in addition to the first and second deacidification processes. Dividing the deacidification process into multiple processes can further reduce nickel loss during the deacidification process.

[0099] Optionally, the first solid-liquid separation step includes:

[0100] The deacidified slurry is filtered to obtain filtrate and filter residue. The filter residue is subjected to a first wash and a second wash in sequence. The wash water from the first wash is incorporated into the filtrate to form a nickel-containing solution. The filter residue after the first wash is subjected to a second wash to obtain calcium sulfate residue. The wash water generated from the second wash is recycled for the first wash. The nickel content of the calcium sulfate residue obtained from the second wash is ≤0.05wt%.

[0101] In some embodiments, a first wash is performed using water equivalent to the weight of the filter cake.

[0102] It should be noted that the calcium sulfate slag obtained from the second washing process can be sold as building material.

[0103] The time for the desiliconization and lead removal process can be adjusted according to the amount of electrolytic nickel anolyte to be treated. In some embodiments, the total reaction time for the desiliconization and lead removal process is 2-4 hours.

[0104] Optionally, the desiliconization and lead removal process includes a multi-stage desiliconization and lead removal treatment performed sequentially. For example, the desiliconization and lead removal treatment may include 2, 3, 4, or 5 stages. Multi-stage desiliconization and lead removal can further reduce nickel loss during the desiliconization and lead removal process.

[0105] In some embodiments, the endpoint pH of the first stage of the multi-stage desiliconization and lead removal process is 3.5-4, and the endpoint pH of the multi-stage desiliconization and lead removal process is 5-6. It is understood that the endpoint pH of the multi-stage desiliconization and lead removal process being 5-6 means that the endpoint pH of the final stage of the desiliconization and lead removal process is 5-6.

[0106] In some embodiments, the desiliconization and lead removal process includes a first-stage desiliconization and lead removal process, a second-stage desiliconization and lead removal process, and a third-stage desiliconization and lead removal process performed sequentially. The endpoint pH value of the first-stage desiliconization and lead removal process is less than or equal to the endpoint pH value of the second-stage desiliconization and lead removal process, and the endpoint pH value of the second-stage desiliconization and lead removal process is less than or equal to the endpoint pH value of the third-stage desiliconization and lead removal process. Slowly adding calcium-containing neutralizing agent II in separate tanks to gradually adjust the pH value can reduce nickel precipitation caused by localized excessive alkalinity, thereby further reducing nickel loss.

[0107] In some embodiments, the endpoint pH value of the first stage desilication and lead removal treatment is 3.5-4, for example, it can be any value between 3.5, 3.6, 3.7, 3.8, 3.9, 4 or 3.5-4;

[0108] The endpoint pH value of the second stage desilication and lead removal treatment is 4-5, for example, it can be 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5 or any value between 4 and 5;

[0109] The endpoint pH value of the third-stage desilication and lead removal treatment is 5-6, for example, it can be any value between 5, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6, or 5-6. In this embodiment, at a pH of 5-6, silicon can co-precipitate with the produced calcium sulfate, and the suspended lead sulfate is also adsorbed and precipitated at the same time.

[0110] In some embodiments, the reaction time for the desiliconization and lead removal process is 2-4 hours, for example, it can be any value between 2 hours, 3 hours, 4 hours or 2-4 hours.

[0111] In some embodiments, the reaction temperature for the desiliconization and lead removal process is room temperature.

[0112] Optionally, the second solid-liquid separation process includes:

[0113] Filtration treatment: The slurry after desiliconization and lead removal is subjected to pressure filtration to obtain desiliconized and lead-removed slag and filtrate.

[0114] Precision filtration: The filtrate from the pressure filter is precision filtered to obtain the nickel-containing pre-purification liquid.

[0115] In some embodiments, the calcium content of the nickel-containing pre-purification solution is 450-650 mg / L.

[0116] Optional, the impurity removal process includes:

[0117] Extraction and impurity removal: The nickel-containing pre-extraction solution is subjected to extraction and impurity removal treatment to obtain a nickel-containing raffinate;

[0118] Oil removal: The nickel-containing raffinate is subjected to oil removal treatment to obtain a nickel-rich purified liquid.

[0119] In some embodiments, the nickel-containing raffinate has the following properties: pH value of 2.5-3.5 and magnesium content ≤2g / L; the nickel-rich purified liquid has the following properties: oil content ≤2mg / L.

[0120] Optionally, the pH value of the nickel-containing raffinate can be any value between 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, or 2.5-3.5.

[0121] Optionally, the magnesium content in the nickel-containing raffinate can be 0.5-2 g / L, for example, it can be any value between 0.5 g / L, 0.6 g / L, 0.7 g / L, 0.8 g / L, 0.9 g / L, 1 g / L, 1.2 g / L, 1.3 g / L, 1.4 g / L, 1.5 g / L, 1.6 g / L, 1.7 g / L, 1.8 g / L, 1.9 g / L, 2 g / L or 0.5-2 g / L.

[0122] Reasonable control of the calcium and magnesium content in nickel-containing raffinate helps balance electrodeposition efficiency and cost. Maintaining a low calcium ion content helps prevent crystallization in the system due to calcium ion supersaturation. Controlling the magnesium content level helps improve the conductivity of the solution and balances processing costs.

[0123] Optionally, the extraction and impurity removal process includes:

[0124] The nickel-containing raffinate before impurity removal is mixed with the saponified extractant for extraction and impurity removal treatment to obtain a nickel-containing raffinate; wherein the saponification rate of the extractant is 10-40%.

[0125] Optionally, the saponification rate of the extractant can be any value between 10%, 15%, 20%, 25%, 30%, 35%, 40%, or 10-40%.

[0126] It should be noted that the extractant includes P204 (Chinese name: di(2-ethylhexyl) phosphate) and / or P507. The above extractants are capable of removing calcium introduced by the calcium neutralizing agent and impurity ions circulating and enriched in the anolyte.

[0127] In some embodiments, the pH value of the nickel-containing raffinate is 2.5-3.5. A pH value within the above range can facilitate the preparation of electrowinning nickel cathode solutions.

[0128] In some embodiments, activated carbon is used for the degreasing process.

[0129] Optionally, the oil content in the nickel-rich purified solution can be any value of 0.2 mg / L, 0.4 mg / L, 0.6 mg / L, 0.8 mg / L, 1 mg / L, 1.2 mg / L, 1.4 mg / L, 1.6 mg / L, 1.8 mg / L, 2 mg / L, or less than or equal to 2 mg / L.

[0130] In some embodiments, the process further includes mixing a portion of the nickel-containing raffinate with the filter press filtrate. In some examples, the weight of the nickel-containing raffinate is 3-7% of the weight of the filter press filtrate. Mixing the nickel-containing raffinate with the filter press filtrate dilutes the calcium in the filter press filtrate, preventing crystallization of the calcium-saturated nickel-containing pre-purification solution during transport. In these embodiments, the precision filtration process includes precision filtration of the mixture of the filter press filtrate and the nickel-containing raffinate to obtain the nickel-containing pre-purification solution.

[0131] In some embodiments, the method of treating electrolytic nickel anolyte further includes:

[0132] pH adjustment process: The nickel-rich purified solution is mixed with a pH buffer and nickel sulfate solution to adjust the pH, resulting in a pH-adjusted solution with a pH of 3-4. This pH-adjusted solution is used as the cathode solution for nickel electrowinning.

[0133] In some embodiments, the nickel sulfate solution comprises a nickel sulfate solution obtained by removing impurities from a nickel-containing leaching solution produced in a dissolution process.

[0134] In some embodiments, the pH buffer is boric acid.

[0135] As previously described, a second aspect of this application provides an apparatus for processing electrolytic nickel anolyte, the apparatus comprising:

[0136] The deacidification unit includes multiple deacidification tanks connected in series. These multiple deacidification tanks are used to mix calcium-containing neutralizing agent I with electrolytic nickel anolyte A to perform continuous multi-stage deacidification treatment to obtain a deacidified slurry.

[0137] The first filtration unit is used to perform solid-liquid separation treatment on the deacidified slurry obtained from the deacidification unit to obtain a nickel-containing solution and calcium sulfate slag.

[0138] The desiliconization and lead removal unit includes multiple desiliconization and lead removal tanks connected in series. These multiple desiliconization and lead removal tanks are used to mix calcium-containing neutralizing agent II with the nickel-containing solution to perform continuous multi-stage desiliconization and lead removal treatment to obtain a desiliconized and lead-removed slurry.

[0139] The second filtration unit is used to perform solid-liquid separation treatment on the desiliconized and lead-removed slurry obtained from the desiliconized and lead-removed unit to obtain desiliconized and lead-removed slag and nickel-containing impurity-removed pre-liquid.

[0140] The first impurity removal unit is used to remove impurities from the nickel-containing pre-removal liquid obtained by the second filtration unit to obtain a nickel-rich post-removal liquid.

[0141] In some embodiments, multiple deacidification tanks connected in series are arranged in a stepped, decreasing manner. This arrangement facilitates the flow of the reacted slurry from the first tank into the next reaction tank and finally into the tail tank.

[0142] In some embodiments, at least two deacidification tanks are connected to a powder feeding device, which includes a powder silo and a screw feeder connected in sequence. The powder silo can be used to store calcium-containing neutralizing agent I, and the screw feeder is used to feed calcium-containing neutralizing agent I into the deacidification tanks.

[0143] In some embodiments, the first filtration unit includes a first belt filter press and a wash water storage tank. The material inlet of the first belt filter press is connected to the deacidification unit, and the filtrate outlet of the first belt filter press is connected to the wash water storage tank, which is connected to the desiliconization and lead removal unit. In use, the deacidified slurry produced by the deacidification unit is pumped into the first belt filter press. The first belt filter press filters and washes the deacidified slurry to obtain filtrate and wash water. The filtrate and wash water are connected to the wash water storage tank through connecting pipelines. In the wash water storage tank, the filtrate and wash water mix to form a nickel-containing solution. The wash water storage tank is connected to the desiliconization and lead removal unit so that the nickel-containing solution in the wash water storage tank can enter the desiliconization and lead removal unit.

[0144] In some embodiments, the first filtration unit further includes a washing tank connected to the filter cake outlet of the first belt filter press. During use, the filter cake enters the washing tank for a second washing process.

[0145] In some embodiments, multiple desiliconization and lead removal tanks connected in series are arranged in a stepped, decreasing manner. This arrangement facilitates the flow of material from the first desiliconization and lead removal tank into the next tank and finally into the tail tank.

[0146] In some embodiments, the desiliconization and lead removal unit is connected to the slurry unit, which includes a powder silo, a screw feeder, a slurry tank, and a calcium neutralizer II slurry storage tank connected in sequence; the calcium neutralizer II slurry storage tank is connected to the desiliconization and lead removal tank and is used to provide calcium neutralizer II slurry to the desiliconization and lead removal tank.

[0147] In some embodiments, the second filtration unit includes a second belt filter press, a desiliconized and lead-removed liquid tank, and a precision filter connected in sequence; wherein the filter element of the precision filter is a PE filter element with a pore size ≤0.5μm.

[0148] In use, the desiliconized and lead-removed slurry produced by the desiliconized and lead-removed unit is pumped into the second belt filter press. The second belt filter press filters the desiliconized and lead-removed slurry, and the resulting filter filtrate enters the desiliconized and lead-removed liquid tank. After being mixed with the nickel-containing raffinate in the desiliconized and lead-removed liquid tank, it enters the precision filter. After being processed by the precision filter, the nickel-containing impurity-removed pre-liquid is obtained.

[0149] In some embodiments, the first impurity removal unit includes a box-type extraction device and an oil removal device. The material inlet of the box-type extraction device is connected to a precision filter, and the material outlet of the box-type extraction device is connected to an oil removal device and a desiliconized and lead-removed liquid tank, respectively.

[0150] In some embodiments, the apparatus for treating electrolytic nickel anolyte further includes:

[0151] The dissolution unit is used to mix the electrolytic nickel anolyte B with a nickel-containing raw material to carry out a leaching reaction, thereby obtaining a nickel-containing leachate. The dissolution unit is included in the reaction vessel for the leaching reaction, and may include a normal pressure reactor, a high pressure reactor, or other reaction vessels, without particular limitation.

[0152] In some embodiments, a second impurity removal unit is further included for removing impurities from the nickel-containing leaching solution. The second impurity removal unit is used to remove impurities from the nickel-containing leaching solution to obtain a nickel sulfate solution. The second impurity removal unit may include one or more devices capable of removing impurities from the solution, including but not limited to extraction, degreasing, and filtration devices, without particular limitation.

[0153] In some embodiments, the apparatus for treating electrolytic nickel anolyte further includes:

[0154] The pH adjustment unit includes a pH adjustment reaction tank and is connected to the first impurity removal unit. The pH adjustment unit is used to adjust the pH of the nickel-rich impurity-removed solution obtained from the first impurity removal unit to obtain a pH-adjusted solution with a pH value of 3-4. This pH-adjusted solution is used as the cathode liquid for nickel electrowinning.

[0155] In some embodiments, the pH adjustment unit is connected to the second impurity removal unit. The nickel sulfate solution produced by the second impurity removal unit can enter the pH adjustment unit and be mixed with the nickel-rich impurity removal solution and a pH buffer to prepare the pH-adjusted solution.

[0156] The following examples will provide a detailed description of this application. Unless otherwise specified, the raw materials, equipment, and instruments involved in the following examples are all commercially available products.

[0157] In the following examples, the particle size D of limestone powder and quicklime powder is... 95 All are below 150μm.

[0158] In the following examples, the compositions of the electrolytic nickel anolyte, limestone powder, and quicklime powder used are shown in Tables 1, 2, and 3, respectively.

[0159] Table 1: Composition of Electrolytic Nickel Anode Solution (Unit: mg / L)

[0160] Table 2: Limestone Powder Composition Table (Unit: wt%)

[0161] Table 3: Composition of quicklime powder (unit: wt%)

[0162] Example 1

[0163] (1) The electrolytic nickel anolyte produced by the electrolytic cell in the electrowinning system contains acid. Electrolytic nickel anolyte B (48wt%) is introduced into the dissolution unit of the high-grade nickel matte nickel sulfate preparation system and mixed with nickel-containing raw material (high-grade nickel matte) for leaching reaction to obtain nickel-containing leachate. After the nickel-containing leachate is treated in the second impurity removal unit of the high-grade nickel matte nickel sulfate preparation system, nickel sulfate solution is obtained. Electrolytic nickel anolyte A (i.e. the remaining 52wt%) is sent to the deacidification process.

[0164] (2) The deacidification process uses four agitated deacidification tanks of the same volume connected in series. The deacidification tanks are distributed in a stepped manner so that the slurry after the reaction can enter the next reaction tank from the first deacidification tank and finally enter the deacidification tail tank. The process reaction temperature is room temperature. The electrolytic nickel anode liquid A from step (1) is pumped into the first deacidification tank. The first deacidification tank is added with limestone powder accounting for about 60% of the total amount of limestone powder (including desiliconized and lead-removed slag) to carry out the first stage of deacidification treatment. The remainder is added to the second deacidification tank and the third deacidification tank respectively to carry out the second stage of deacidification treatment and the third stage of deacidification treatment. No addition is made to the deacidification tail tank. The final pH value of the deacidification tail tank is controlled to be 2.6. The total reaction time is 6 hours to obtain the deacidified slurry.

[0165] (3) After the reaction is completed, the deacidified slurry is pumped into a belt filter press for solid-liquid separation to obtain filtrate and filter residue. The filter residue is subjected to a first wash and a second wash in sequence. That is, the filter residue is machine washed on the first belt filter press with spray water of equal weight to the filter residue. The wash water and filtrate are mixed to form a nickel-containing solution and sent to the next process. The filter residue produced by the first belt filter press is put into a stirring tank and stirred at a mass liquid-solid ratio of 4mL:1g. After stirring, the filter is filtered again using the first belt filter press. Part of the stirring filtrate is used as spray water for machine washing. The remaining stirring filtrate is replenished with an equal amount of clean water and then circulated for use as washing water. The calcium sulfate slag produced by stirring and filtration is gypsum slag containing 0.05wt% nickel and is used for sale.

[0166] (4) The desiliconization and lead removal process uses three continuously connected desiliconization and lead removal tanks of the same volume, which are stirred and distributed in a stepped manner so that the slurry after the reaction can enter the next desiliconization and lead removal tank from the first desiliconization and lead removal tank and finally enter the desiliconization and lead removal tail tank. The nickel-containing solution produced in step (3) is pumped into the first desiliconization and lead removal tank. The quicklime slurry with a concentration of 20wt% obtained by mixing quicklime powder and water is added to the three desiliconization and lead removal tanks respectively. The pH of the first desiliconization and lead removal tank is controlled at 4.0 for the first stage of desiliconization and lead removal treatment, the pH of the second desiliconization and lead removal tank is controlled at 4.5 for the second stage of desiliconization and lead removal treatment, and the pH of the last desiliconization and lead removal tank is controlled at 5.1 for the third stage of desiliconization and lead removal treatment. The total reaction time is 3 hours, and the desiliconization and lead removal slurry is obtained.

[0167] (5) The desiliconized and lead-removed slurry is pumped into the second belt filter press for filtration to obtain desiliconized and lead-removed slag and filter filtrate. The filter filtrate is mixed with nickel-containing raffinate and then processed through a precision filter to obtain nickel-containing impurity removal pre-liquid, which is sent to the next process. The nickel-containing impurity removal pre-liquid contains: silicon 33 mg / L, lead 0.15 mg / L, and calcium 480 mg / L. The desiliconized and lead-removed slag is washed with clean water, unloaded, packaged, and sent to the deacidification process as a neutralizing agent.

[0168] (6) The nickel-containing pre-cleaning liquid produced in step (5) is sent to the extraction line for impurity removal. The extraction line uses P204 extractant with a saponification rate of 15%. The pH value of the nickel-containing raffinate is controlled at 3.0. The nickel-containing raffinate contains 28 mg / L of calcium and 1435 mg / L of magnesium. 5 wt% of the nickel-containing raffinate is returned to the desiliconization and lead removal tank to dilute the calcium in the nickel-containing pre-cleaning liquid, so as to avoid the calcium-saturated nickel-containing pre-cleaning liquid from crystallizing during transportation. After extraction, the nickel-containing raffinate is then de-oiled by multi-stage activated carbon to produce nickel-rich post-cleaning liquid. The oil content of the nickel-rich post-cleaning liquid is 0.8 mg / L.

[0169] (7) The nickel-rich purified solution produced in step (6) is added to the nickel sulfate solution produced in the second purification unit, and boric acid is added appropriately to control the pH value at 3.4 to obtain a cathode solution with a nickel concentration of 92 g / L. The cathode solution can be sent to the cathode chamber of the electrolytic cell as a cathode solution for electrowinning nickel to continue electrowinning and produce electrolytic nickel.

[0170] The process flow for treating electrolytic nickel anolyte is shown in Figure 1.

[0171] The second aspect of this embodiment provides an apparatus for processing electrolytic nickel anolyte, used to perform the above-described method, comprising: a dissolution unit, a deacidification unit, a first filtration unit, a desiliconization and lead removal unit, a second filtration unit, a first impurity removal unit, a pH adjustment unit, and a second impurity removal unit;

[0172] The dissolution unit is connected to the second impurity removal unit;

[0173] The deacidification unit includes a first deacidification tank, a second deacidification tank, a third deacidification tank, and a deacidification tail tank, which are distributed in a stepped manner. The first deacidification tank, the second deacidification tank, and the third deacidification tank are connected to a powder feeding device, which includes a powder silo and a screw feeder connected in sequence.

[0174] The first filtration unit includes a first belt filter press, a washing tank, and a washing water storage tank. The material inlet of the first belt filter press is connected to the deacidification tail tank, the filtrate outlet of the first belt filter press is connected to the washing tank, and the filter residue outlet of the first belt filter press is connected to the washing water storage tank.

[0175] The desiliconization and lead removal unit includes a first desiliconization and lead removal tank, a second desiliconization and lead removal tank, a third desiliconization and lead removal tank, and a desiliconization and lead removal tail tank, which are distributed in a stepped manner. All three desiliconization and lead removal tanks are connected to the pulping unit. The first desiliconization and lead removal tank is connected to the wash water storage tank. The pulping unit includes a powder silo, a screw feeder, a pulping tank, and a calcium-containing neutralizing agent II slurry storage tank connected in sequence.

[0176] The second filtration unit includes a second belt filter press, a desiliconization and lead removal liquid tank, and a precision filter (PE filter element, pore size ≤0.5μm) connected in sequence. The material inlet of the second belt filter press is connected to the third desiliconization and lead removal tank, the filtrate outlet of the second belt filter press is connected to the desiliconization and lead removal liquid tank, and the desiliconization and lead removal liquid tank is connected to the precision filter.

[0177] The first impurity removal unit includes a box-type extraction device and an oil removal device. The material inlet of the box-type extraction device is connected to a precision filter, and the material outlet of the box-type extraction device is connected to an oil removal device and a desiliconized and lead-removed liquid tank, respectively.

[0178] The pH adjustment unit includes a pH adjustment reaction tank and is connected to the first impurity removal unit and the second impurity removal unit.

[0179] The working principle of the device for processing electrowinning nickel anolyte includes:

[0180] Electrolytic nickel anolyte B enters the dissolution unit and is mixed with high-grade nickel matte for a leaching reaction. The resulting nickel-containing leaching solution enters the second impurity removal unit for impurity removal treatment to obtain a nickel sulfate solution.

[0181] The calcium-containing neutralizing agent I in the powder silo is transported by a screw feeder to the first deacidification tank, the second deacidification tank, and the third deacidification tank in the deacidification unit. It is mixed with the electrolytic nickel anode liquid A and enters the first belt filter press of the first filtration unit through the deacidification tail tank. The filtrate and wash water produced by the first belt filter press enter the wash water storage tank to form a nickel-containing solution. The filter residue produced by the first belt filter press enters the stirring and washing tank. The calcium sulfate residue produced by the stirring and washing tank is sold externally.

[0182] The nickel-containing solution is transported through pipelines to the first desiliconization and lead removal tank of the desiliconization and lead removal process, and is mixed with calcium-containing neutralizing agent II output from the slurry unit in the first desiliconization and lead removal tank, the second desiliconization and lead removal tank and the third desiliconization and lead removal tank to obtain the desiliconized and lead-removed slurry.

[0183] After desiliconization and lead removal, the slurry is transported through pipelines to the second belt filter press of the second filtration unit for filtration. The filtrate produced by the second belt filter press enters the desiliconization and lead removal post-slurry tank and then enters the precision filter for filtration, resulting in nickel-containing pre-removal liquid.

[0184] The nickel-containing pre-removal liquid is transported to the first removal unit through a pipeline. After being processed by the box-type extraction device of the first removal unit, a nickel-containing raffinate is obtained. Part of the nickel-containing raffinate is returned to the desiliconization and lead removal post-removal liquid tank, and the other part of the nickel-containing raffinate is processed by the deoiling device to obtain a nickel-rich post-removal liquid.

[0185] The nickel-rich purified solution and nickel sulfate solution are transported through pipelines to the pH adjustment reaction tank of the pH adjustment unit, where they are mixed with pH buffer to obtain the pH-adjusted solution.

[0186] Figure 2 shows a partial flowchart of the apparatus for processing electrolytic nickel anolyte.

[0187] Example 2

[0188] This embodiment provides a method for processing electrolytic nickel anolyte, using the same apparatus as in Embodiment 1, including:

[0189] (1) The electrolytic nickel anolyte produced by the electrolytic cell in the electrowinning system contains acid. Electrolytic nickel anolyte B (50wt%) is introduced into the dissolution unit of the high-grade nickel matte nickel sulfate preparation system and mixed with nickel-containing raw material (high-grade nickel matte) for leaching reaction to obtain nickel-containing leachate. After the nickel-containing leachate is treated in the second impurity removal unit of the high-grade nickel matte nickel sulfate preparation system, nickel sulfate solution is obtained. Electrolytic nickel anolyte A (i.e. the remaining 50wt%) is sent to the deacidification process.

[0190] (2) The deacidification process uses five agitated deacidification tanks of the same volume connected in series. The deacidification tanks are distributed in a stepped manner so that the slurry after the reaction can enter the next deacidification tank from the first deacidification tank and finally enter the deacidification tail tank. The process reaction temperature is room temperature. The electrolytic nickel anode liquid A from step (1) is pumped into the first deacidification tank. 60% of the total amount of limestone powder added is added to the first deacidification tank for the first stage of deacidification treatment. The remainder is added to the subsequent deacidification tanks for deacidification treatment. No addition is made to the deacidification tail tank. The final pH value of the deacidification tail tank is controlled to be 2.9. The total reaction time is 4.7h to obtain the deacidified slurry.

[0191] (3) After the reaction is completed, the deacidified slurry is pumped into the first belt filter press for solid-liquid separation to obtain filtrate and filter residue. The filter residue is subjected to a first wash and a second wash in sequence, that is, spray water with an amount equivalent to the weight of the filter residue is used for machine washing on the first belt filter press. The wash water and filtrate are mixed to form a nickel-containing solution and sent to the next process. The filter residue produced by the first belt filter press enters the stirring tank and is stirred and washed at a mass liquid-solid ratio of 4mL:1g. After stirring and washing, the first belt filter press is used for filtration again. Part of the stirring filtrate is used as spray water for machine washing. The remaining stirring filtrate is replenished with an equal amount of clean water and then circulated for use as washing water. The calcium sulfate slag produced by stirring and filtration is gypsum slag (containing 0.03wt% nickel) and is used for sale.

[0192] (4) The desiliconization and lead removal process uses three continuously connected desiliconization and lead removal tanks of the same volume, which are stirred and distributed in a stepped manner so that the slurry after the reaction can enter the next desiliconization and lead removal tank from the first desiliconization and lead removal tank and finally enter the desiliconization and lead removal tail tank. The nickel-containing solution produced in step (3) is pumped into the first desiliconization and lead removal tank. The quicklime slurry with a concentration of 28wt% obtained by mixing quicklime powder and water is added to the three desiliconization and lead removal tanks respectively. The pH of the first desiliconization and lead removal tank is controlled at 3.6 for the first stage of desiliconization and lead removal treatment, the pH of the second desiliconization and lead removal tank is controlled at 4.5 for the second stage of desiliconization and lead removal treatment, and the pH of the last desiliconization and lead removal tank is controlled at 5.5 for the third stage of desiliconization and lead removal treatment. The total reaction time is 2.5h, and the desiliconization and lead removal slurry is obtained.

[0193] (5) The desiliconized and lead-removed slurry is pumped into the second belt filter press for filtration to obtain desiliconized and lead-removed slag and filter filtrate. The filter filtrate is mixed with nickel-containing raffinate and then processed through a precision filter as nickel-containing impurity removal pre-liquid to the next process. The nickel-containing impurity removal pre-liquid contains: silicon 48 mg / L, lead 0.18 mg / L, and calcium 591 mg / L. The desiliconized and lead-removed slag is washed with clean water, unloaded, packaged, and sent to the deacidification process as a neutralizing agent.

[0194] (6) The nickel-containing pre-cleaning liquid produced in step (5) is sent to the extraction line for impurity removal. The extraction line uses P204 extractant with a saponification rate of 25%. The pH value of the nickel-containing raffinate is controlled at 3.4. The nickel-containing raffinate contains 5 mg / L of calcium and 1165 mg / L of magnesium. 5 wt% of the nickel-containing raffinate is returned to the desiliconization and lead removal tank to dilute the calcium in the nickel-containing pre-cleaning liquid, so as to avoid the calcium-saturated nickel-containing pre-cleaning liquid from crystallizing during transportation. After extraction, the nickel-containing raffinate is then de-oiled by multi-stage activated carbon to produce a nickel-rich post-cleaning liquid with an oil content of 0.5 mg / L.

[0195] (7) The nickel-rich purified solution produced in step (6) is added to the nickel sulfate solution produced in the second purification unit, and boric acid is added appropriately to control the pH at 3.2 to obtain a cathode solution with a nickel concentration of 89.5 g / L. The cathode solution can be sent to the cathode chamber of the electrolytic cell as a cathode solution for electrowinning nickel to continue electrowinning and produce electrolytic nickel.

[0196] Example 3

[0197] This embodiment provides a method for processing electrolytic nickel anolyte, using the same apparatus as in Embodiment 1, including:

[0198] (1) The electrolytic nickel anolyte produced by the electrolytic cell in the electrowinning system contains acid. Electrolytic nickel anolyte B (51 wt%) is introduced into the dissolution unit of the high-grade nickel matte nickel sulfate preparation system and mixed with nickel-containing raw material (high-grade nickel matte) to carry out a leaching reaction to obtain nickel-containing leachate. After the nickel-containing leachate is treated in the second impurity removal unit of the high-grade nickel matte nickel sulfate preparation system, nickel sulfate solution is obtained. Electrolytic nickel anolyte A (i.e. the remaining 49 wt%) is sent to the deacidification process.

[0199] (2) The deacidification process uses four deacidification tanks of the same volume connected in series. The deacidification tanks are distributed in a stepped manner so that the slurry after the reaction can enter the next deacidification tank from the first deacidification tank and finally enter the deacidification tail tank. The electrolytic nickel anode liquid A from step (1) is pumped into the first deacidification tank. 60% of the total amount of limestone powder added to the first deacidification tank is added to the first deacidification tank for the first stage of deacidification treatment. The remainder is added to the subsequent deacidification tanks for deacidification treatment. No addition is made to the deacidification tail tank. The final pH of the deacidification tail tank is controlled at 2.8. The total reaction time is 3.5h to obtain the deacidified slurry.

[0200] (3) After the reaction is completed, the deacidified slurry is pumped into the first belt filter press for solid-liquid separation to obtain filtrate and filter residue. The filter residue is subjected to a first washing and a second washing in sequence, that is, spray water with an amount equivalent to the weight of the filter residue is used for machine washing on the first belt filter press. The washing water and filtrate are mixed to form a nickel-containing solution and sent to the next process. The filter residue produced by the first belt filter press enters the stirring tank and is stirred and washed at a mass liquid-solid ratio of 4mL:1g. After stirring and washing, the first belt filter press is used for filtration again. Part of the stirring and washing filtrate is used as spray water for machine washing. The remaining stirring and washing liquid is replenished with an equal amount of clean water and then circulated for use as washing water. The calcium sulfate slag produced by stirring and filtration is gypsum slag (containing 0.04wt% nickel) and is used for sale.

[0201] (4) The desiliconization and lead removal process uses four continuously connected desiliconization and lead removal tanks of the same volume, which are stirred and distributed in a stepped manner so that the slurry after the reaction can enter the next desiliconization and lead removal tank from the first desiliconization and lead removal tank and finally enter the desiliconization and lead removal tail tank. The nickel-containing solution produced in step (3) is pumped into the first desiliconization and lead removal tank. The quicklime slurry with a concentration of 12wt% obtained by mixing quicklime powder and water is added to the three desiliconization and lead removal tanks respectively. The pH of the first desiliconization and lead removal tank is controlled at 3.9, the pH of the second desiliconization and lead removal tank is 4.5, and the pH of the last desiliconization and lead removal tank is 6.0. The total reaction time is 4h, and the desiliconization and lead removal slurry is obtained.

[0202] (5) The desiliconized and lead-removed slurry is pumped into the second belt filter press for filtration to obtain desiliconized and lead-removed slag and filter filtrate. The filter filtrate is sent to the next process as nickel-containing impurity removal pre-liquid after passing through a precision filter. The nickel-containing impurity removal pre-liquid contains: silicon 16mg / L, lead 0.04mg / L, and calcium 626mg / L. The desiliconized slag produced is washed with clean water, unloaded, packaged, and sent to the deacidification process as a neutralizing agent.

[0203] (6) The nickel-containing pre-cleaning liquid produced in step (5) is sent to the extraction line for impurity removal. The extraction line uses P204 extractant with a saponification rate of 35%. The pH value of the nickel-containing raffinate is controlled at 2.6. The nickel-containing raffinate contains 47 mg / L of calcium and 1865 mg / L of magnesium. 3 wt% of the nickel-containing raffinate is returned to the desiliconization and lead removal tank to dilute the calcium in the nickel-containing pre-cleaning liquid, so as to avoid the calcium-saturated nickel-containing pre-cleaning liquid from crystallizing during transportation. After extraction, the nickel-containing raffinate is then de-oiled by multi-stage activated carbon to produce nickel-rich post-cleaning liquid. The oil content of the nickel-rich post-cleaning liquid is 0.6 mg / L.

[0204] (7) The nickel-rich purified solution produced in step (6) is added to the nickel sulfate solution produced in the second purification unit, and boric acid is added appropriately to control the pH at 3.8 to obtain a cathode solution with a nickel concentration of 90.8 g / L. The cathode solution can be sent to the cathode chamber of the electrolytic cell as a cathode solution for electrowinning nickel to continue electrowinning and produce electrolytic nickel.

[0205] Comparative Example 1

[0206] (1) Add liquid alkali solution to the electrolytic nickel anolyte and control the pH value to 7-8 during the reaction (the pH can be adjusted and stabilized by liquid alkali and electrolytic nickel anolyte). After reacting at 60℃ for 3 hours, filter and wash (backwashing removes sodium from the filter cake during filtration, or the filter cake can be re-pulped and washed after filtration and then pressed and filtered. The sodium sulfate concentration of the cathode liquid during electrolytic deposition will affect the appearance quality and yield of nickel plates). Obtain nickel hydroxide / nickel carbonate filter cake and nickel precipitation liquid (filtrate). The nickel precipitation liquid is then subjected to resin deweighting (recovery of nickel and cobalt), magnesium precipitation (addition of calcium carbonate), and decarbonization (decarbonization tower) to obtain sodium sulfate wastewater.

[0207] (2) Add the nickel hydroxide / nickel carbonate filter cake to another part of the nickel electrowinning anolyte to dissolve it, control the Ni concentration to about 90 g / L, and add a pH buffer to stabilize and control the final pH value to 3-4 (after nickel precipitation, some impurities in the original anolyte are discharged with the filtrate, and then nickel hydroxide / nickel carbonate is used as alkali to neutralize another part of the nickel electrowinning anolyte, reducing the amount of liquid alkali used, and returning the nickel to the system). After the reaction is completed, filter to obtain the cathode liquid for nickel electrowinning. The composition of the cathode liquid is shown in Table 4 below:

[0208] The apparatus for treating electrolytic nickel anolyte in this comparative example includes: a nickel immersion stirring tank, a nickel immersion filter press, a nickel washing tank, a washing filter press, a wash water storage tank, a wastewater nickel immersion tank, and a wastewater filter press.

[0209] Table 4: Composition of the catholyte in Comparative Example 1 (mg / L)

[0210] In this comparative example, the wastewater needs to be treated separately, the wastewater treatment process is long and the cost is high; in addition, a lot of water is introduced into the system and the output wastewater volume is too large, requiring the configuration of large water treatment equipment to prepare the wastewater into low-value chemical by-products, resulting in high equipment investment costs.

[0211] As can be seen from the above results, the method and apparatus for treating electrolytic nickel anolyte provided in this application, which uses a two-stage method with a calcium-containing neutralizing agent to sequentially perform deacidification and desiliconization and lead removal, can reduce production costs and does not produce wastewater, thus eliminating the need for supporting wastewater treatment equipment such as nickel recovery and MVR.

[0212] Meanwhile, the method of this application can remove the calcium introduced by calcium salt and the impurity ions that are circulated and enriched in the anolyte. The calcium sulfate slag produced by the deacidification treatment is sold as a building material after washing, and the slag produced by the desiliconization and lead removal treatment is sent to other nickel sulfate production lines as a neutralizing agent after washing, which is environmentally friendly.

[0213] The preferred embodiments of this application have been described in detail above; however, this application is not limited thereto. Within the scope of the technical concept of this application, various simple modifications can be made to the technical solution of this application, including combining various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in this application and are all within the protection scope of this application.

Claims

1. A method for treating electrolytic nickel anolyte, the method comprising: Deacidification process: Calcium neutralizing agent I is mixed with electrolytic nickel anolyte A to carry out deacidification treatment, and a deacidified slurry is obtained; First solid-liquid separation process: The deacidified slurry is subjected to a first solid-liquid separation treatment to obtain a nickel-containing solution and calcium sulfate slag; Desiliconization and lead removal process: Calcium neutralizing agent II is mixed with the nickel-containing solution to perform desiliconization and lead removal treatment, resulting in a desiliconized and lead-removed slurry; The second solid-liquid separation process involves subjecting the desiliconized and lead-removed slurry to a second solid-liquid separation treatment to obtain desiliconized and lead-removed slag and a nickel-containing pre-removal liquid with a silicon content ≤50mg / L. Impurity removal process: The nickel-containing pre-impurity removal solution is subjected to impurity removal treatment to obtain a nickel-rich post-impurity removal solution with a calcium content ≤50mg / L.

2. The method according to claim 1, wherein the method satisfies at least one of the following conditions: A. The method further includes a dissolution step: mixing the electrolytic nickel anolyte B with a nickel-containing raw material to carry out a leaching reaction, thereby obtaining a nickel-containing leachate; B. The method further includes a pH adjustment step: the nickel-rich impurity-removed solution is mixed with a pH buffer and a nickel sulfate solution for pH adjustment treatment to obtain a pH-adjusted solution with a pH value of 3-4.

3. The method according to claim 1 or 2, wherein, The method satisfies at least one of the following conditions: A. The calcium neutralizing agent I is mixed in powder form with the electrolytic nickel anolyte A for deacidification treatment; B. The endpoint pH value of the deacidification treatment is 2.5-3.0; C. The reaction time for the deacidification treatment is 3-6 hours; D. The calcium-containing neutralizing agent I and the calcium-containing neutralizing agent II each independently comprise at least one of CaCO3, CaO and Ca(OH)2; E. The calcium-containing neutralizing agent I comprises limestone powder and desiliconized and lead-removing slag; F. The particle size D of the calcium-containing neutralizing agent I and the calcium-containing neutralizing agent II 95 All are less than 150 μm; G. The calcium-containing neutralizing agent II is pulped before use, and the pulping includes: mixing the calcium-containing neutralizing agent II with water to obtain a neutralizing agent slurry; the concentration of the calcium-containing neutralizing agent II in the neutralizing agent slurry is 10-30 wt%; H. The deacidification process includes at least three deacidification treatments, with at least 50% of the total amount of the calcium-containing neutralizing agent I added in the first deacidification treatment; I. The composition of the electrolytic nickel anolyte A or the electrolytic nickel anolyte B includes: Ni 40-70 g / L, Ca 4-10 mg / L, Mg 1000-1700 mg / L, Si 50-150 mg / L, Co 1-7 mg / L, Cu 0.5-1.5 mg / L, Zn 0.05-0.2 mg / L, Fe 0.5-1 mg / L, Pb 0.3-2 mg / L, and sulfuric acid 40-60 g / L; J. The nickel sulfate solution includes the nickel sulfate solution obtained by removing impurities from the nickel-containing leaching solution produced in the dissolution process.

4. The method according to claim 1 or 2, wherein, The first solid-liquid separation process includes: The deacidified slurry is filtered to obtain filtrate and filter residue. The filter residue is then subjected to a first wash and a second wash in sequence. The wash water from the first wash is incorporated into the filtrate to form the nickel-containing solution. The filter residue after the first wash is then subjected to a second wash to obtain the calcium sulfate residue. The wash water from the second wash is recycled for the first wash. The nickel content of the calcium sulfate residue is ≤0.05wt%.

5. The method according to claim 1 or 2, wherein, The desiliconization and lead removal process includes a multi-stage desiliconization and lead removal process performed sequentially.

6. The method according to claim 5, wherein, The method satisfies at least one of the following conditions: A. The final pH value of the first stage of the multi-stage desiliconization and lead removal process is 3.5-4, and the final pH value of the multi-stage desiliconization and lead removal process is 5-6. B. The desiliconization and lead removal process includes a first-stage desiliconization and lead removal process, a second-stage desiliconization and lead removal process, and a third-stage desiliconization and lead removal process performed sequentially. The final pH value of the first-stage desiliconization and lead removal process is 3.5-4, the final pH value of the second-stage desiliconization and lead removal process is 4-5, and the final pH value of the third-stage desiliconization and lead removal process is 5-6. C. The reaction time for the desiliconization and lead removal treatment is 2-4 hours.

7. The method according to claim 1 or 2, wherein, The second solid-liquid separation process includes: Filtration treatment: The desiliconized and lead-removed slurry is subjected to pressure filtration to obtain the desiliconized and lead-removed slag and the pressure filtrate; Precision filtration: The filtrate from the pressure filter is subjected to precision filtration to obtain the nickel-containing pre-removal liquid.

8. The method according to claim 7, wherein, The impurity removal process includes: Extraction and impurity removal: The nickel-containing pre-extraction solution is subjected to extraction and impurity removal treatment to obtain a nickel-containing raffinate; Oil removal: The nickel-containing raffinate is subjected to oil removal treatment to obtain the nickel-rich purified liquid.

9. The method according to claim 8, wherein, The method satisfies at least one of the following conditions: A. The nickel-containing raffinate meets the following requirements: pH value 2.5-3.5, magnesium content ≤2g / L; the nickel-rich purified solution meets the following requirements: oil content ≤2mg / L. B. The extraction and impurity removal includes: mixing the nickel-containing pre-extraction liquid with the saponified extractant for extraction and impurity removal treatment to obtain the nickel-containing raffinate; wherein the saponification rate of the extractant is 10-40%; C. It also includes mixing a portion of the nickel-containing raffinate with the filter press filtrate, wherein the weight of the portion of the nickel-containing raffinate is 3-7% of the weight of the filter press filtrate; D. The weight ratio of the electrolytic nickel anolyte A to the electrolytic nickel anolyte B is 1:0.6-1.5; E. The calcium content of the nickel-containing pre-purification solution is 450-650 mg / L.

10. An apparatus for processing electrowinning nickel anolyte, the apparatus comprising: The deacidification unit includes multiple deacidification tanks connected in series. These multiple deacidification tanks are used to mix calcium-containing neutralizing agent I with electrolytic nickel anolyte A to perform continuous multi-stage deacidification treatment to obtain a deacidified slurry. The first filtration unit is used to perform solid-liquid separation treatment on the deacidified slurry obtained from the deacidification unit to obtain a nickel-containing solution and calcium sulfate slag. The desiliconization and lead removal unit includes multiple desiliconization and lead removal tanks connected in series. These multiple desiliconization and lead removal tanks are used to mix calcium-containing neutralizing agent II with the nickel-containing solution to perform continuous multi-stage desiliconization and lead removal treatment to obtain a desiliconized and lead-removed slurry. The second filtration unit is used to perform solid-liquid separation treatment on the desiliconized and lead-removed slurry obtained from the desiliconized and lead-removed unit to obtain desiliconized and lead-removed slag and nickel-containing impurity-removed pre-liquid. The first impurity removal unit is used to remove impurities from the nickel-containing pre-removal liquid obtained by the second filtration unit to obtain a nickel-rich post-removal liquid.

11. The apparatus of claim 10, wherein the apparatus satisfies at least one of the following conditions: A. The device further includes: A dissolution unit is used to mix electrolytic nickel anolyte B with nickel-containing raw materials to carry out a leaching reaction and obtain a nickel-containing leachate. B. The device further includes: a pH adjustment unit, the pH adjustment unit including a pH adjustment reaction tank, the pH adjustment unit being connected to the first impurity removal unit.

12. The apparatus according to claim 11, wherein, The device satisfies at least one of the following conditions: A. The first filtration unit includes a first belt filter press and a wash water storage tank. The material inlet of the first belt filter press is connected to the deacidification unit, the filtrate outlet of the first belt filter press is connected to the wash water storage tank, and the wash water storage tank is connected to the desiliconization and lead removal unit. B. The multiple series-connected desiliconization and lead removal tanks are distributed in a stepped decreasing pattern; C. The desiliconization and lead removal unit is connected to the pulping unit, which includes a powder silo, a screw feeder, a pulping tank, and a calcium neutralizer II slurry storage tank connected in sequence; the calcium neutralizer II slurry storage tank is connected to the desiliconization and lead removal tank and is used to supply calcium neutralizer II slurry to the desiliconization and lead removal tank. D. The second filtration unit includes a second belt filter press, a desiliconized and lead-removed liquid tank, and a precision filter connected in sequence; wherein the filter element of the precision filter is a PE filter element with a pore size ≤0.5μm; E. The first impurity removal unit includes a box-type extraction device and an oil removal device. The material inlet of the box-type extraction device is connected to a precision filter, and the material outlet of the box-type extraction device is connected to an oil removal device and a desiliconized and lead-removed liquid tank, respectively. F. The apparatus further includes a second impurity removal unit for removing impurities from the nickel-containing leaching solution, the second impurity removal unit being connected to the pH adjustment unit.

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